ENH : add comments

Code/BasicFilters/otbKeyPointDensityImageFilter.h

@@ -31,8 +31,17 @@ namespace otb
 {
 
 /** \class KeyPointDensityImageFilter
- *  \brief
+ *  \brief This class computes the density of the characteristic
+ *  points detected in the image.
  *
+ * The density computed is a ratio of the number of keypoints over
+ * the total number of pixels within a region.
+ *
+ * This class use the key point detector specified in the 3rd argument
+ * template to detect the keypoints. Then for every pixel, the density of the key points
+ * within its neighborhood is computed.
+ * 
+ * The output is a map of key points density.
  */
 
 template <class TInputImage, class TOutputImage , class TDetector>

Code/BasicFilters/otbKeyPointDensityImageFilter.txx

@@ -51,7 +51,7 @@ KeyPointDensityImageFilter<TInputImage, TOutputImage, TDetector >
  */
 
 /**
-* ThreadedGenerateData Performs the pixel-wise addition
+* GenerateData Performs the pixel-wise addition
 */
 template <class TInputImage , class TOutputImage, class TDetector>
 void